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White-Rodgers is a business
of Emerson Electric Co.
The Emerson logo is a
trademark and service mark
of Emerson Electric Co.
HOMEOWNER HELP LINE: 1-800-284-2925
www.white-rodgers.com
www.emersonclimate.com
DIAGNOSTIC TABLE
DS 1 (Red) DS 2 (Green) Error/Condition Comments/Troubleshooting
Simultaneous
slowash
Simultaneous
slowash
Normal operation No fault
Simultaneous
fastash
Simultaneous
fastash
Normal operation with
call for heat
Normal operation
Slowash On
Open limit switch Verify continuity through rollout switch circuit
Off Slowash
Pressure switch stuck
closed/open
Pressure switch stuck closed. Check switch function, verify
inducer is turning off.
Pressure switch stuck open. Check pressure switch function
and tubing. Verify inducer is turning on and pulling sufficient
vacuum to engage switch.
Alternate
slowash
Alternate slow
ash
External lockout
(retries)
Failure to sense flame is often caused by carbon deposits on
the flame sensor, a disconnected or shorted flame sensor
lead or a poorly grounded furnace. Carbon deposits can be
cleaned with emery cloth. Verify sensor is not contacting the
burner and is located in a good position to sense flame.
Ignitor must be positioned to light the gas immediately when
the valve opens. If the ignitor has been replaced, verify hot
spot position has not changed.
Check sensor lead for shorting and verify furnace is
grounded properly.
Slowash Off
Flame sensed with gas
valve de-energized
Verify the gas is operating and shutting down properly. Flame
in burner assembly should extinguish promptly at the end of
the cycle. Check orifices and gas pressure.
On Slowash
Open rollout switch Verify continuity through rollout switch circuit.
On On
Module – internal fault
condition
Module contacts for gas valve not operating or processor
fault. Reset control, if condition persists, replace module.
Slowash Fastash
Low flame sense
current
Low flame sense current is often caused by carbon deposits
on the flame sensor, a poorly grounded furnace or a mis-
aligned flame sense probe. Carbon deposits can be cleaned
with emery cloth.
Check or improve furnace and module ground. Verify sensor
is located in or very near flame as specified by the appliance
manufacturer.
Fastash Slowash
Grounding or
reversed polarity
Verify the control and furnace are properly grounded. Check
and reverse polarity (primary) if incorrect.
Alternate fast
ash
Alternate fast
ash
Module ignitor
contact failure
Fault code indicates the module ignitor contacts are not
functioning properly. Replace module.
TROUBLESHOOTING